The objective of this proposal is to perform an additional one year of follow-up data collection for the Economics and Quality of Life (EQOL) Coordinating Center for SCD-HeFT, a multi-center clinical trial of prophylactic amiodarone or implantable defibrillator therapy versus conventional heart failure therapy in patients with Class II or Class III congestive heart failure (CHF) and an ejection fraction of less than or equal to 35%. In collaboration with the Clinical Coordinating Center and the Statistical and Data Coordinating Center, the EQOL Coordinating Center will continue to perform the following major functions: 1) assess economic, functional status, and quality of life outcomes dudng follow-up clinic visits at 1 year and 2.5 years after enrollment; 2) identify all medical encounters that occur during follow-up and collect detailed health care resource consumption and cost data for each; 3) compare cost and quality of life outcomes for the three treatment arms according to intention-to-treat; 4) determine factors in addition to treatment that are associated with variations in cost and quality of life outcomes; 5) estimate incremental cost-effectiveness ratios for experimental arms and perform extensive sensitivity analyses. With an additional year of follow-up, we could expect a 28% increase in subjects who reach the 2.5-year QOL endpoint visit, bringing us to 92% of total study enrollment. Similarly, data collection of economic resource use and costs would be available for the additional year on all 2521 patients who completed enrollment by July 2001. We feel that we can substantially increase the statistical power of our analyses, complete parallel analyses with the clinical arm of SCD-HeFT, and thereby significantly enhance the overall productivity of our research within the basic scope of the original Specific Aims.